At the Bonn 2.5 GeV electron synchrotron the first measurements of the target asymmetry for the reaction γ + n ↑ → π − + p have been performed. The negative pions were detected in a magnetic spectrometer at a constant pion c.m. angle of 40° and photon energies between 0.45 GeV and 2.0 GeV. Deuterated butanol was used as target material. The polarization of the deuterons was about 16%. The results show a significant difference from the previously measured π + asymmetry.
No description provided.
K − p reactions have been studied at 13 different incident momenta between 1138 and 1434 MeV/ c . This interval corresponds to a mass of the K − p system varying from 1858 to 1993 MeV. About 300 000 photographs were taken in the 81 cm Saclay hydrogen bubble chamber exposed to a separated K − beam at the CERN proton-synchrotron. A total of about 44 000 events were analyzed, from which partial and differential cross sections were determined. Polarizations were obtained for the two-body reactions where the decay of the Λ or Σ hyperon allowed their measurement. Data for the two-body channels are presented here as well as for the main quasi-two-body reactions.
PARTIAL CROSS SECTIONS. DATA AT 1.305 TO 1.434 GEV/C FOR FINAL STATES K- P, K- P PI0 AND K- N PI+ COME FROM THE HAIFA GROUP, S. DADO ET AL.
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We present results of a K − d experiment performed with the 81 cm Saclay deuterium bubble chamber which was exposed to a K − beam at 4 momenta between 680 and 840 MeV/ c at the CERN PS. Cross sections were measured for inelastic two- and three-body K − n reactions on the basis of 5200 events/mb. Resonance production in the three-body reactions is discussed. In addition, differential cross sections and polarisations are presented for inelastic two-body reactions.
CROSS SECTIONS FOR TWO-BODY REACTIONS.
CROSS SECTIONS FOR THREE-BODY REACTIONS.
CROSS SECTIONS FOR K- P REACTIONS.
We have made measurements of polarization in π−p elastic scattering, with emphasis over the backward region, at 1.60 to 2.28 GeVc. The results indicate the absence of u-channel dominance in the backward region, as was observed in the case of π+p scattering. Comparisons have been made with predictions of various phase-shift analyses which show that the agreement is generally very poor in the backward region.
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At the Bonn 2.5.GeV electron synchrotron the target asymmetry for the photoproduction of positive pions has been measured. Data were taken at photon energies between 0.7 and 2.2 GeV and a pion CM-angle of 65°.
Axis error includes +- 0.0/0.0 contribution (?////).
No description provided.
We have measured the polarization parameter in π−p elastic scattering at laboratory momenta of 1180, 1250, and 1360 MeV/c in the angular interval 65°<θc.m.<115°. The results were used to show that the polarized target used in these (and other similar) experiments was uniformly polarized. These measurements were also used to resolve pre-existing experimental discrepancies in the determination of the polarization parameter, and to clarify the behavior of scattering amplitudes in this energy range. We show that local measurements of this type are important in resolving discrete ambiguities affecting the energy continuation of the amplitudes. An important by-product of this experiment is the development of a fast method of reconstructing particle trajectories and fitting the elastic events, which could have a significant impact for future high-statistics experiments.
No description provided.
Analyzing powers of pion-proton elastic scattering have been measured at PSI with the Low Energy Pion Spectrometer LEPS as well as a novel polarized scintillator target. Angular distributions between 40 and 120 deg (c.m.) were taken at 45.2, 51.2, 57.2, 68.5, 77.2, and 87.2 MeV incoming pion kinetic energy for pi+ p scattering, and at 67.3 and 87.2 MeV for pi- p scattering. These new measurements constitute a substantial extension of the polarization data base at low energies. Predictions from phase shift analyses are compared with the experimental results, and deviations are observed at low energies.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 87.2 MeV from the data set 1.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 68.4 MeV from the data set 1.
Analyzing power for PI+ P elastic scattering at incidient kinetic energy 57.2 MeV from the data set 1.
We report on the measurement of asymmetries in the single-pion photoproduction reactions γp→nπ+, γp→pπ0, and γn→pπ−, induced by linearly polarized photons of energies from 610 to 940 MeV. The experiment was carried out using the back-scattered laser beam and the 82-in. dubble chamber at SLAC. We compare the new data with predictions from a partial-wave analysis.
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Cross sections for the $\gamma p \to K^+ \Lambda$ have been measured at backward angles using linearly polarized photons in the range 1.50 to 2.37 GeV. In addition, the beam asymmetry for this reaction has been measured for the first time at backward angles. The $\Lambda$ was detected at forward angles in the LEPS spectrometer via its decay to $p\pi^-$ and the K^+ was inferred using the technique of missing mass. These measurements, corresponding to kaons at far backward angles in the center-of-mass frame, complement similar CLAS data at other angles. Comparison with theoretical models shows that the reactions in these kinematics provide further opportunities to investigate the reaction mechanisms of hadron dynamics.
Differential cross sections as a function of the Mandelstam variable U for photon beam energy 1.5 to 1.8 GeV.
Differential cross sections as a function of the Mandelstam variable U for photon beam energy 1.8 to 2.1 GeV.
Differential cross sections as a function of the Mandelstam variable U for photon beam energy 2.1 to 2.4 GeV.
We present measurements of the differential and total cross sections and the Λ polarization for the reaction K−p→ηΛ from threshold to pK−=770MeV/c, with much better precision than previous measurements. Our cross-section data show a remarkable similarity to the SU(3) flavor-related π−p→ηn cross-section results. The reaction K−p→ηΛ at threshold is dominated by formation of the intermediate Λ(1670)12− state.
Total cross section measurement for K- P --> ETA LAMBDA. Errors shown are statistical only.
Differential cross sections DSIG/DOMEGA for K- P --> ETA LAMBDA. Errors shown are statistical only.
Differential cross sections DSIG/DOMEGA for K- P --> ETA LAMBDA. Errors shown are statistical only.
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